The goal, which came from an Obafemi Martins cross, allowed the Sounders to run their winning streak to five and their unbeaten run to six, having scored the result-clinching goal after the 80th minute in five of those games.

Dallas were playing their second game in four days and used a lineup that featured four personnel changes from Sunday’s loss to the New York Red Bulls. After converting an early penalty and withstanding a barrage of opportunities, they still looked poised to get get at least a point as the game moved toward stoppage time, mostly on the back of a stellar performance from goalkeeper Raúl Fernández.

But that’s when Martins got a ball down the left channel and sent in a cross to Cooper, who was unmarked in front of goal. The former FC Dallas man, who had entered the game only a few minutes earlier, hit it first time for his third goal of the season.

Martins also set up the Sounders’ equalizer when he was able to split a pair of defenders with a pass to Lamar Neagle at the near post. Neagle had slipped in behind the defense and finished it from the edge of the six-yard box. Neagle now has four goals and Martins has a league-leading six assists.

Just a few minutes later Fernández came up with a pair of huge saves to keep the score level. First he dove to his left to keep out Osvaldo Alonso’s blast from just oustide the area. The ball ricocheted off the post and Dempsey was first to the rebound for what looked to be a simple tap-in, but Fernandez recovered quickly and was able to make a kick save on the follow-up.

FC Dallas got on the scoreboard first when Blas Pérez drew a penalty while chasing a ball over the top, with defenders on either side of him. Brad Evans got his feet tangled up with the Panamanian striker and referee Baldemermo Toledo pointed to the spot, leaving Michel to coolly finish the opportunity for a 16th-minute lead.

The Sounders have now allowed four penalties, the same total as the 2012 and 2013 seasons combined. It was also the fifth penalty Dallas have been awarded this season and the fourth they’ve converted, the same number they converted in the last two years combined.

The Sounders stayed atop the Supporters’ Shield standings and now have 22 points through 10 games. They return to action on Sunday with a road game against the New England Revolution.

FC Dallas lost their third straight and have now gone 1-4-0 after a 4-0-1 start. They play at the San Jose Earthquakes on Saturday.